Articles formed of a (meth)acrylic resin composition have excellent transparency and low optical distortion and therefore find applications as optical lenses, disc substrates, automobile parts, advertising displays, nameplates, lighting covers, light guide plates, and the like.
As one of methods for manufacturing a (meth)acrylic resin composition, known is a continuous bulk polymerization process, specifically the process comprising continuously feeding a raw material solution comprising a polymerizable monomer, a polymerization initiator and the like into a tank reactor for bulk polymerization while continuously discharging the resulting reaction product. The continuous bulk polymerization process is suitable for mass production of a (meth)acrylic resin composition having excellent optical properties.
Patent Document 1 discloses a method for producing a (meth)acrylic polymer, the method comprising steps of continuously feeding a raw material composition comprising a (meth)acrylic monomer, a radical polymerization initiator and a chain transfer agent into a polymerization tank, polymerizing at least a part of the (meth)acrylic monomer in the polymerization tank to obtain a reaction mixture containing a (meth)acrylic polymer resulting from polymerization of the at least a part of the (meth)acrylic monomer, continuously discharging the reaction mixture from the polymerization tank, introducing the reaction mixture thus discharged from the polymerization tank into an extruder unit equipped with vents so as to remove volatile matter, and adding an additive through an additive inlet positioned downstream of an outlet vent of the extruder unit equipped with vents.